Pressure regulator for a fuel system

ABSTRACT

The invention relates to a pressure regulator for a fuel system. The pressure regulator includes a housing assembled out of at least two housing parts. A membrane unit is securely installed in a sealed fashion between the housing parts. The securing region that securely holds the two housing parts and the membrane unit in a sealed fashion has an elastic region so that the desired secure connection is assured by simply snapping the two housing parts together. The device is provided in particular for regulating a pressure in a fuel system.

PRIOR ART

The invention is based on a pressure regulator for a fuel systems.

There is a large number of publications that disclose a pressureregulator whose housing is comprised of two housing parts connected bymeans of a crimped edge, wherein a membrane unit that divides twochambers from each other in the housing is also clamped at the crimpededge. The German published patent application 23 54 461 will be used asa representative for the many publications.

Because there is fuel in the housing, it is very important that theconnection that clamps the two housing parts together and secures themembrane unit is sealed, particularly if the device is disposed outsidea fuel tank, for example in the vicinity of a hot internal combustionengine.

Because leaks can occur even with carefully created crimped edges, e.g.after damage due to shocks to the housing, it has already been proposedthat the two housing parts be welded together over their entirecircumference. This process, however, is very costly and despite coolingmeasures, the membrane unit cannot be prevented from being damaged byheat generated during the welding process.

For the crimping of the two housing parts, high forces must be used forshaping the edges of the housing parts. In particular, attention must bepaid that during crimping, the regions of the housing disposed outsidethe crimp are not unduly deformed. Since high forces are required forthe crimping, the fact that the housing is not unduly deformed duringthe crimping must be assured with costly measures, in particular bymeans of careful securing of the housing parts in special machines. Itis therefore also not advisable to entirely or partially cast or moldthe housing in plastic because then the forces acting on the housingduring the crimping can no longer be reliably intercepted.

An extremely high degree of care must be exercised when crimping thehousing parts. In particular, the limits of the permissible tolerancesof the material used for the housing parts, the material used for themembrane, the dimensions of the housing parts, the dimensions of themembrane, the forces exerted during the crimping, the die forms used forthe crimping, to name only a few examples, must be very narrowly set,which leads to high costs for the manufacture. Even the slightestoverstepping of the narrow tolerance limits can lead to a malfunction,in particular to a leak. Also, sags that appear during the use of thedevice can lead to a malfunction, in particular to a leak. Because aninadequate crimping of the housing parts sometimes only leads to a leakafter a long service life of the device, there is a great danger thatoccasionally, a large number of inadequately crimped housings reachesthe customer before the defect is detected. Also, sags that appearbetween the housing parts to be crimped and the membrane unit during theoperation of the device can occasionally lead to leaks even if in afirst testing of the crimp, it appeared as though the crimp was inorder.

ADVANTAGES OF THE INVENTION

The device for a fuel system, according to the invention has theadvantage over the prior art that the housing parts can be assembledwithout a high cost and by using relatively low forces that are easy toproduce.

Another advantage is that the limits of the tolerances in the materialsof the housing parts and the membrane unit can be far apart from eachother without having to fear that the device will be leaky.

Because the assembly of the housing parts can occur very simply, inparticular without expensive devices and machines, the assembly of thedevice can advantageously be established at any desirable location on aproduction line.

Because only low forces are required to assemble the housing parts, itis possible to cast the housing of the device, for example in plastic,without having to fear that damage can occur when assembling the housingparts.

Also, deformations of the housing, which can occur, for example, whensomething strikes against the finished housing, advantageously hardlyever lead to a leak.

Advantageous improvements and updates of the device for a fuel systemare possible by means of the measures taken in the assembly.

If one of the housing parts is embodied so that it is U-shaped when thecross section of the housing part is considered in the securing region,then this has the advantage that even with relatively thin wallthicknesses of the housing, a high stability of the housing can beachieved.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferably selected, particularly advantageous exemplary embodiments ofthe invention are shown in simplified form in the drawings and will beexplained in more detail in the subsequent description. In differentscales, FIGS. 1 to 7 show different cross sectional views of exemplaryembodiments and details of differently embodied devices for a fuelsystem.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The device that is embodied according to the invention and is for a fuelsystem, in particular of an internal combustion engine, has a housingcomprised of a number of, housing parts preferably two of them. In thehousing, there is a membrane or membrane unit which divides two chambersfrom each other. The membrane or membrane unit is secured and sealed onits outer circumference. For reasons of simplicity, the securing andsealing of the membrane or membrane unit occurs at the location in whichtwo of the at least two housing parts of the housing are assembled.

FIG. 1 shows a preferably selected, particularly advantageous firstexemplary embodiment.

In a sectional view, FIG. 1 shows an upper partial region of a fuel tank2. The fuel tank 2 has an opening 4 in its upper wall. The opening 4 isclosed with a cover comprised of plastic. For the sake of simplicity,the cover will be called the base body 6 below. The cover or base body 6is secured to the upper wall of the fuel tank 2 with the aid of screwsthat are not shown. In order to be able to manufacture the base body 6for a justifiable cost despite its not exactly simple shape, and forweight reasons, the base body 6 is comprised of plastic. A pressureregulator 8 is integrated in terms of function and shape securely intothe base body 6. The pressure regulator 8 has a housing 10. In theexemplary embodiment depicted, the housing 10 is comprised of a firsthousing part 11 and a second housing part 12. Although in the selectedexemplary embodiment, the first housing part 11 is aligned toward thetop, the first housing part 11 is frequently called the bottom part andthe second housing part 12 is frequently called the top part. Thehousing 10 is essentially rotationally symmetrical. An imaginaryrotational axis of the housing 10 is called the longitudinal axis A andis indicated in the drawing with a dot-and-dash line. There is amembrane unit 14 in the housing 10. In the exemplary embodimentdepicted, the membrane unit 14 includes a membrane 15, a first plate 16,a second plate 17, and a closing body 18. The plates 16 and 17 areconnected to the membrane 15 in the central region of the membrane 15.On its outer circumference, the membrane 15 is inserted between thefirst housing part 11 and the second housing part 12. The first plate 16holds the closing body 18, which is a flattened ball, for example. Themembrane 15 is comprised of one or a number of layers of flexibleplastic sheet, preferably two of them. A cloth layer can be disposedbetween the plastic sheets. In particularly supported cases, if sodesired, the plates 16, 17 attached to the membrane 15 and to theclosing body 18 can be eliminated so that only the membrane 15, withoutthe parts 16, 17, 18, is inserted between the housing parts 11, 12.

The membrane 15 of the membrane unit 14 divides a first chamber 21 froma second chamber 22. The first chamber 21 is disposed essentially insidethe first housing part 11 and the second chamber 22 is disposedessentially inside the second housing part 12. Inside the base body 6,there is a supply conduit 24 and a return conduit 26. In the exemplaryembodiment depicted, the supply conduit 24 has an inlet end 24a and acontinuing end 24b. On its end face, the first housing part 11 has abottom region 11a with a central recess 27. Laterally offset, the bottomregion 11a has an opening 28. A fitting 29 that protrudes through thecentral recess 27 is formed onto the base body 6. A stop 30 is providedon an end face of the fitting 29 oriented toward the closing body 18 ofthe membrane unit 14. The return conduit 26 passes through the base body6 until the stop 30 provided on the end face of the fitting 29 orientedtoward the closing body 18. In the selected exemplary embodiment, thestop 30 provided on the base body 6 is used as a valve seat for theclosing body 18.

The inlet end 24a of the supply conduit 24 is connected to a fuel pumpthat is provided in the fuel tank 2 and is not shown for the sake ofbetter visibility. Fuel supplied by the fuel pump travels through theinlet end 24a and from there, through the supply conduit 24 to thecontinuing end 24b and then, for example, to the injection valves, notshown. By means of the supply conduit 24, the fuel also travels throughthe opening 28 into the first chamber 21. If the pressure in the firstchamber 21 is lower than a designated opening pressure, then the closingbody 18 rests against the stop 30 and the first chamber 21 is closed offin relation to the return conduit 26. If the pressure in the firstchamber 21 exceeds the designated opening pressure, then the closingbody 18 of the membrane unit 14 lifts up from the stop 30 and excessfuel can travel out of the supply conduit 24, through the first chamber21, through the gap between the stop 30 and the closing body 18, andthen through the return conduit 26 back into the fuel tank 2. A closingforce acts on the plate 17 and therefore the closing body 18 in thedirection of the stop 30. In the exemplary embodiment depicted, theclosing force is generated by a closing spring 32. In lieu of theclosing spring 32 or in addition to the closing spring 32, a pressureprevailing in the second chamber 22 can be used to generate the closingforce.

The device depicted in FIG. 1 has a securing region 40 on the housing10. For the sake of better visibility, the part of the device where thesecuring region 40 is located is reproduced again in FIGS. 2a and 2bwith an altered scale, and in FIG. 3, the first housing part 11 isreproduced separately, leaving out all other parts.

In all of the Figs., the same parts or parts that function equivalentlyare provided with the same reference numerals. If nothing to thecontrary is mentioned or depicted in the drawings, that which ismentioned and depicted in conjunction with one of the Figs. also appliesto the other exemplary embodiments. Provided that the explanations donot state otherwise, the details of the different exemplary embodimentscan be combined with one another.

In the securing region 40 of the device or the housing 10 in turn, thereare a number of bottom regions. The bottom regions of the securingregion 40 include a detent region 42, an elastic region 44, and aclamping region 46. FIG. 2A shows the device before the two housingparts 11, 12 are connected to each other in detent fashion in thesecuring region 40. FIG. 2B shows the two housing parts 11, 12 after thetwo housing parts 11, 12 are connected to each other in detent fashionin the detent region 42 of the securing region 40.

Next to the bottom region 11a with the central recess 27 (FIG. 3), thefirst housing part 11 has a cylindrical region 11c, and next to that, aregion 11e that extends radially, crosswise to the longitudinal axis Aof the housing 10 and is adjoined by another region 11g extending in theshape of a cylinder. The second housing part 12 has a cylindrical region12c and next to that, an essentially radially extending region 12e, andadjoining this, a region 12g that extends essentially in the shape of acylinder. The region 12e is slightly inclined conically and constitutesa continuous face like the jacket face of a truncated cone. The region12g constitutes a continuous outer collar of the housing part 12.

The clamping region 46 (FIGS. 2a, 2b) is essentially constituted by aclamping point 46a on the housing part 11 and a clamping point 46b onthe housing part 12. The clamping point 46a is provided on the radiallyextending region 11e on the end oriented toward the region 12e. Theclamping point 46b is disposed in the region 12e, on the end orientedtoward the radially extending region 11e.

In the cylindrically extending region 11g of the first housing part 11,there are a number of U-shaped cut-outs 48 distributed continuously andevenly over the circumference (FIG. 3). By means of the cut-outs 48, anumber of tabs 50 are formed on the housing part 11 that radiallyprotrude slightly inward. When FIG. 3 is considered, it is clear thateach of the tabs 50 has an end face that radially protrudes slightlyinward and is oriented toward the bottom region 11a. This end face ofthe tab 50 constitutes a detent point 42a that is provided on the firsthousing part 11 and belongs to the detent region 42. Viewed in terms ofcross section, the second housing part 12 is U-shaped in the securingregion 40. When FIGS. 2a and 2b are considered, the U-shaped form of thesecond housing part 12 is visible in the securing region 40, wherein thecylindrical region 12c constitutes an inner leg, the cylindricallyextending region 12g constitutes an outer leg, and the region 12econstitutes a connecting section of the two legs of the housing part 12.The cylindrically extending region 12g of the housing part 12 has acircumferential end face that is remote from the region 12e andconstitutes the detent point 42b belonging to the detent region 42(FIGS. 2a, 2b).

The housing parts 11, 12 are assembled by virtue of the fact that theyare oriented flush and then slid together. The longitudinal axis A isalso the direction for the assembly.

Before the assembly, the membrane unit 14 is placed against the radiallyextending region 11e of the housing part 11. To that end, the device canbe rotated by 180° in relation to the position shown. Then, the housingpart 12 is inserted into the region 11g of the housing part 11. As FIG.2a shows, the region 11e of the first housing part 11 and the region 12eof the second housing part 12 do not run parallel to each other, but areinclined in relation to each other at an angle α (alpha). At the placewhere the region 12e transitions into the cylindrical region 12c, theregion 12e has a continuous region that protrudes the farthest in thedirection of the first housing part 11. If the two housing parts 11 and12 are assembled by being slid toward each other in the direction of thelongitudinal axis A, then this protruding, continuous region of theregion 12e is the first to circumferentially touch the membrane 15,which is resting over the entire width against the essentially radiallyextending region 11e of the first housing part 11. The second housingpart 12, with the protruding, continuous region of the region 12e,presses the membrane 15 against the first housing part 11 before the twodetent points 42a, 42b of the detent region 42 reach engagement witheach other. In order to bring the two detent points 42a, 42b intoengagement with each other, the region 12g of the second housing part 12must be pressed with easy-to-exert force in the direction of thelongitudinal axis A against the first housing part 11. The angle α(alpha) is thereby reduced, wherein the elastic region 44 providedbetween the clamping region 46 and the detent region 42 is elasticallydeformed. The angle α (alpha) is reduced until it is zero or close tozero, depending on the tolerance situation of the components to beassembled with each other. The elastic region 44 provided on the housing10 assures that the membrane 15 is clamped securely and in a sealedfashion between the clamping point 46a on the first housing part 11 andthe clamping point 46b on the second housing part 12 and remains so. Themembrane 15 remains securely clamped in a sealed fashion even if anyappearances of sagging occur with longer operation of the device. If anyappearances of sagging should occur, then the angle α (alpha) maypossibly increase. As a result of the elastic initial stress in theelastic region 44, though, sufficient initial stress always remains tosecurely hold the membrane 15 in a sealed fashion between the twohousing parts 11 and 12. It should be further emphasized that in themanufacture of the housing parts 11, 12, no particularly narrowdimensional tolerances have to be maintained in the securing region 40since the elastic region 44 is sufficiently elastic so that under anycircumstances, even when there is a great dimensional tolerance,sufficient initial stress is present and remains to secure the membrane15. Moreover, it should be further emphasized that the materialproperties of the housing parts 11, 12 can also lie within a coarselytolerable scope without having to fear an insufficient clamping of themembrane 15. Since relatively low forces are sufficient for the assemblyof the two housing parts 11, 12 and no complicated shaping proceduresare necessary, the assembly process for putting together the two housingparts 11, 12 can occur independently from complicated machines duringthe manufacture process of the device.

The detent point 42a at the tab 50 of the first housing part 11 radiallyprotrudes slightly inward (FIG. 3). During the assembly of the twohousing parts 11, 12, if the cylindrically extending region 12g of thesecond housing part 12 arrives in the region of the tabs 50, then thedetent points 42a on the first housing part 11 are pressed elasticallyoutward radially (FIG. 2a). During the assembly, the second housing part12 is pressed in the direction of the longitudinal axis A against thefirst housing part 11. As a result, the elastic region 44 is elasticallydeformed until the detent point 42a at the tab 50 snaps radially inagain over the detent point 42b on the second housing part 12. As aresult, the detent point 42a on the first housing part 11 engages indetent fashion with the detent point 42b on the second housing part 12,by means of which the two housing parts 11, 12 are reliably and securelyheld together. The elastic region 44 presses the detent point 42bagainst the detent point 42a so that the connection between the twohousing parts 11, 12 is reliable and free of play.

FIGS. 4a, 4b, and 5 show details of another selected, particularlyadvantageous exemplary embodiment. FIG. 4a shows the securing region 40before the two housing parts 11, 12 are connected to each other indetent fashion, and FIG. 4b shows the securing region 40 after thedetent connection of the two housing parts 11, 12. FIG. 5 shows a detailof the first housing part 11, with the remaining components of thedevice left out.

As shown in FIG. 5, a number of undercuts 52, which protrude radiallyinward, are evenly distributed over the circumference, and are providedat the same location in terms of the axial direction, are molded ontothe region 11g of the first housing part 11. The end of the undercut 52oriented toward the region 11e is embodied as relatively sharp-edged,and the detent point 42a is disposed on the side of the undercut 52oriented toward the region 11e. The undercuts 52 (FIG. 5) are lesselastic than the tabs 50 (FIG. 3). As a result, in the exemplaryembodiment according to FIG. 5, when the second housing part 12 ispressed into the first housing part 11, the region 11g of the firsthousing part 11 and the region 12g of the second housing part 12 areelastically deformed in the radial direction until the detent point 42bof the second housing part 12 snaps over the detent point 42a on thefirst housing part 11. Depending on the material thickness chosen, theregion 11g and/or the region 12g are slightly out of round during theinsertion process. After the end of the insertion process, the regions11g, 12g return elastically to their round shape. In contrast to theexemplary embodiment with the U-shaped cut-outs 48 (FIG. 3), in theexemplary embodiment shown in FIGS. 4a, 4b, and 5, a somewhat higherdegree of rigidity can be achieved with the same material thickness andthe missing cut-outs offer advantages in the casting or molding of thebase body 6 onto the first housing part 11 because then, no plasticmaterial can flow through the cut-outs.

FIG. 6 shows another preferably selected, advantageous exemplaryembodiment.

In the exemplary embodiment shown in FIG. 1, the device with the basebody 6, the housing 10, the membrane unit 14 incorporated into thehousing 10, and the stop 30 on the base body 6 constitutes the pressureregulator 8. In the exemplary embodiment shown in FIG. 6, the base body6, the housing 10, the membrane unit 14, and the stop 30 are theessential parts of a reservoir 55. Depending on whether the reservoir 55takes in or gives out a relatively large amount or a relatively smallamount of fuel when there are pressure changes in the supply conduit 24,the reservoir 55 is used only to smooth sharp pressure pulsations in thesupply conduit 24, or when there is a pressure increase, the reservoir55 can receive greater quantities of fuel which it then gives out againwhen the pressure decreases so that the reservoir 55 can effectivelyfunction as a fuel reservoir.

With the pressure regulator 8 (FIG. 1) and with the reservoir 55 (FIG.6), the base body 6, which is comprised of relatively soft material,preferably plastic, is molded or cast onto the first housing part 11.The pressure regulator 8 or the reservoir 55 can consequently beintegrated in a simple manner into a plastic body. In order to permit afavorable cohesion between the housing part 11 and the base body 6, thediameter of the recess 27 is smaller than the diameter of the fitting29. The base body 6 is, for example, a cover for closing the fuel tank2, or the base body 6 is, for example, a fuel distributing tube that isincorporated into an engine compartment of a vehicle and a number oflines branch from this tube, leading to injection valves.

FIG. 7 shows another preferably selected, particularly advantageousexemplary embodiment.

In this exemplary embodiment, a first fitting 61 is soldered, welded, orcrimped in a known manner into the first housing part 11, i.e. in thelaterally provided opening 28, and a second fitting 62 is fastened inthe same way into the recess 27. In the exemplary embodiment shown inFIG. 7, the supply conduit 24 extends through the first fitting 61 andthe return conduit 26 extends through the second fitting 62. The deviceconstitutes a pressure regulator 65 for installation in a hose line. Thepressure regulator 65 (FIG. 7) is installed in a line. For example, ahose is connected to each of the fittings 61 and 62.

Also with the reservoir 55 (FIG. 6) and with the pressure regulator 65(FIG. 7), the securing region 40 can be embodied in the way that isshown in FIGS. 1, 2a, 2b, 3, 4a, 4b, 5, and explained in the descriptionin conjunction with these Figs. In all cases, with the device embodiedaccording to the invention, the advantage is obtained that the twohousing parts 11, 12 can be assembled using relatively low forces andthe membrane unit 14 or the membrane 15 is securely held in a sealedfashion between the two housing parts 11, 12, even with a longeroperating time.

Due to the low force required for assembly, damage need not be feared,particularly damage to the base body 6 (FIGS. 1, 6) and the membrane 15.

In the exemplary embodiments shown, the first housing part 11 has anapproximately Z-shaped form in the securing region 40 and the secondhousing part 12 has an approximately U-shaped form. It should be furthernoted that in lieu of this, the first housing part 11 in the securingregion 40 can also be embodied as U-shaped and the second housing part12 can be correspondingly embodied as Z-shaped. The elastic region 44 isproduced in the examples shown by means of elastic deformation of thesecond housing part 12. However, the elastic region can also be producedby the elastic deformation of the first housing part 11, preferably theregion 11e. It is also possible to elastically deform both housing parts11 and 12 between the detent region 42 and the clamping region 46 inorder to thus obtain the elastic region 44. The foregoing relates to apreferred exemplary embodiment of the invention, it being understoodthat other variants and embodiments thereof are possible within thespirit and scope of the invention, the latter being defined by theappended claims.

We claim:
 1. A device for a fuel system, comprising a housing (10)comprised of a first housing part (11) and at least one second housingpart (12), wherein the two housing parts (11, 12) are held together in asecuring region (40), a membrane unit (14, 15) that divides a firstchamber from a second chamber is clamped in the securing region (40)between the first housing part (11) and the second housing part (12),the securing region (40) includes a detent region (42) with at least onefirst detent point (42a) provided on the first housing part (11) andwith at least one second detent point (42b) that is provided on thesecond housing part (12) and engages in detent fashion with the firstdetent point (42a), a clamping region (46) with at least one clampingpoint (46a) provided on the first housing part (11) and having at leastone second clamping point (46b) provided on the second housing part(12), wherein between the detent region (42) and the clamping region(46), at least one elastic region (44) is provided and the membrane unit(14, 15) is clamped in the clamping region (46) by means of an elasticinitial stress that is produced by an elastic deformation of the elasticregion (44).
 2. The device for a fuel system according to claim 1, inwhich for a detent connection of the two detent points (42a, 42b) of thetwo housing parts (11, 12), the two housing parts (11, 12) are acted ontoward each other in an assembly direction (A) with an assembly forceand the elastic deformation of the elastic region (44) is produced bythe assembly force.
 3. The device for a fuel system according to claim1, in which the elastic region (44) is constituted by a first face (11e)that adjoins the first clamping point (46a) and a second face (12e) thatadjoins the second clamping point (46b), wherein the two faces (11e,12e) extend at an angle (α (alpha)) in relation to each other.
 4. Thedevice for a fuel system according to claim 2, in which the elasticregion (44) is constituted by a first face (11e) that adjoins the firstclamping point (46a) and a second face (12e) that adjoins the secondclamping point (46b), wherein the two faces (11e, 12e) extend at anangle (α (alpha)) in relation to each other.
 5. The device for a fuelsystem according to claim 3, in which the angle (α (alpha)) opens in adirection of the detent region (42).
 6. The device for a fuel systemaccording to claim 4, in which the angle (α (alpha)) opens in adirection of the detent region (42).
 7. The device for a fuel systemaccording to claim 3, in which the elastic initial stress in an assemblyof the first housing part (11) with the second housing part (12) isproduced by a change of the angle (α (alpha)).
 8. The device for a fuelsystem according to claim 4, in which the elastic initial stress in anassembly of the first housing part (11) with the second housing part(12) is produced by a change of the angle (α (alpha)).
 9. The device fora fuel system according to claim 1, in which one of the housing parts(12) is cross sectionally embodied as U-shaped in the securing region(40) and has two legs (12c, 12g) and a connecting section (12e), whereinthe detent region (42) is provided on one of the two legs (12g) and theclamping region (46) is provided on the connecting section (12e). 10.The device for a fuel system according to claim 2, in which one of thehousing parts (12) is cross sectionally embodied as U-shaped in thesecuring region (40) and has two legs (12c, 12g) and a connectingsection (12e), wherein the detent region (42) is provided on one of thetwo legs (12g) and the clamping region (46) is provided on theconnecting section (12e).
 11. The device for a fuel system according toclaim 3, in which one of the housing parts (12) is cross sectionallyembodied as U-shaped in the securing region (40) and has two legs (12c,12g) and a connecting section (12e), wherein the detent region (42) isprovided on one of the two legs (12g) and the clamping region (46) isprovided on the connecting section (12e).
 12. The device for a fuelsystem according to claim 5, in which one of the housing parts (12) iscross sectionally embodied as U-shaped in the securing region (40) andhas two legs (12c, 12g) and a connecting section (12e), wherein thedetent region (42) is provided on one of the two legs (12g) and theclamping region (46) is provided on the connecting section (12e). 13.The device for a fuel system according to claim 7, in which one of thehousing parts (12) is cross sectionally embodied as U-shaped in thesecuring region (40) and has two legs (12c, 12g) and a connectingsection (12e), wherein the detent region (42) is provided on one of thetwo legs (12g) and the clamping region (46) is provided on theconnecting section (12e).
 14. The device for a fuel system according toclaim 9, in which at least one radially directed projection (50, 52) isprovided on the respective other housing part (11) and engages behindone of the legs (12g).
 15. The device for a fuel system according toclaim 1, in which one of the housing parts (11) is molded into a plasticpart (6).
 16. The device for a fuel system according to claim 2, inwhich one of the housing parts (11) is molded into a plastic part (6).17. The device for a fuel system according to claim 3, in which one ofthe housing parts (11) is molded into a plastic part (6).
 18. The devicefor a fuel system according to claim 5, in which one of the housingparts (11) is molded into a plastic part (6).
 19. The device for a fuelsystem according to claim 15, in which a stop (30) is provided on theplastic part (6) and the membrane unit (14, 15) can come into contactwith this stop (30).
 20. The device for a fuel system according to claim19, in which the stop (30) is embodied as a valve seat.